. . an organized government truly is the head of the organism. Today, this is less and less the case.
As to the criminals being better armed and more vicious than the rest of the community, then it is the responsibility of the community to counter it by building a government that can counter the criminals, support that government and provide it cooperation and information needed to be effective.
If even that can't be done, then perhaps it is time to call in an outside government to put things right until the situation is under control, and cooperate with that government. The bitter truth is, the community should never have let that situation develop in the first place.
It is also necessary to appropriately define the "community". In the case of Los Angeles gangs, it might do to simply define "members" as the community, since there actually are powerful government entities to counter them.
The guilt of the whole must be applied to each and every member just as the guilt of a government is applied to each and every soldier in it's armed forces - if they're shooting at you, you shoot at all of 'em. Some didn't shoot at you, but you apply the guilt of the highest level that has control. You either do that or accept death for yourself.
Unfortunately, in the case of gangs, the community label will probably have to be extended to those who hide and aid members, making it more likely "innocents" will be harmed. Sometimes it's difficult to separate the real innocents from the pretend innocents and accidents will happen. You try to minimize accidents, but accept that they will happen, or accept death for yourself and your loved ones.
There are a zillion rationalizations and copouts to justify that the broader community is "innocent" and has no control. Unfortunately, there's no one else to assign that responsibility too. Take the responsibility or suffer the consequences. Life is not easy.